1. Field of the Invention
The present invention relates to a valve device for coupling a container filled with a flowable material, such as fertiliser, pesticide or the like, to an applicator device for dispensing the said material, and for controlling the flow of material from the container into the applicator device.
When sowing seeds in a field it is often a requirement to apply an agricultural treatment agent, such as a fertiliser or pesticide, along with the seeds. Typically, the seeds and the material to be applied along with them are held in separate hoppers carried by a planting/applicator device and each is dispensed from its respective hopper by a metering device. The fertiliser or pesticide may also be applied on its own, typically from a broadcaster device.
Increasingly, it is considered desirable for agricultural workers to avoid direct contact with certain agricultural treatment agents. These agricultural treatment agents are usually stored ready for use in sealed containers which must be opened and emptied into the relevant hopper on the planter/applicator device. Inevitably, such a procedure involves at least some exposure to the agricultural treatment agent.
2. Discussion of the Prior Art
U.S. Pat. No. 5,029,624 discloses a valve system for controlling the flow of a flowable agricultural treatment agent from a container for the material to a receiving chamber or hopper. The container has a material dispensing valve and the chamber or hopper has a material receiving valve. The dispensing valve and the receiving valve are adapted to be coupled and uncoupled so that on being coupled both valves are opened to allow material to flow from the container to the hopper and on being uncoupled both valves are biased to a closed position.
The valve system is so designed that material will not flow from the container into the hopper until the container is properly mounted on the hopper. Furthermore, the dispensing valve inter-acts with the receiving valve in such a way as to introduce a time delay between the opening and closing of the valves to assure a free flow of material and prevent any leakage of material before the container is removed from the hopper.
The valve system of U.S. Pat. No. 5,029,624 is very effective at preventing the escape of an agricultural treatment agent, both as it is emptied from a container into a hopper and after. However, it is very complex in design, requiring as it does a dispensing valve for the container and a receiving valve for the hopper, and as a consequence it is relatively expensive. The system is made even more expensive by providing each container with its own dispensing valve as envisaged in the aforementioned prior art document.